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    [XFRM]: Allow packet drops during larval state resolution. · 14e50e57
    David S. Miller 提交于
    The current IPSEC rule resolution behavior we have does not work for a
    lot of people, even though technically it's an improvement from the
    -EAGAIN buisness we had before.
    
    Right now we'll block until the key manager resolves the route.  That
    works for simple cases, but many folks would rather packets get
    silently dropped until the key manager resolves the IPSEC rules.
    
    We can't tell these folks to "set the socket non-blocking" because
    they don't have control over the non-block setting of things like the
    sockets used to resolve DNS deep inside of the resolver libraries in
    libc.
    
    With that in mind I coded up the patch below with some help from
    Herbert Xu which provides packet-drop behavior during larval state
    resolution, controllable via sysctl and off by default.
    
    This lays the framework to either:
    
    1) Make this default at some point or...
    
    2) Move this logic into xfrm{4,6}_policy.c and implement the
       ARP-like resolution queue we've all been dreaming of.
       The idea would be to queue packets to the policy, then
       once the larval state is resolved by the key manager we
       re-resolve the route and push the packets out.  The
       packets would timeout if the rule didn't get resolved
       in a certain amount of time.
    Signed-off-by: NDavid S. Miller <davem@davemloft.net>
    14e50e57
udp.c 24.8 KB